A structure which is depicted in FIG. 4 of Patent document 1 is known as a structure of an inverter section of an inverter-integrated electric compressor to which a motor drive circuit including an inverter is mounted inside. In such a structure, power MOS transistor modules are arrayed, axially in three rows and circumferentially in two columns, as being adjacent to each other, and low-pressure refrigerant gas is flowed thereinto so as to cool down the power MOS transistor modules.
Additionally, in a pump housing of a fluid pump device depicted in FIG. 2 of Patent document 2, plate-shaped power transistors are arrayed outward in an radial direction, and are fixed through block formed into a shape of partially notched ring.